The name of a covert operation should be distinctive but utterly random, like Sweet Tooth. That’s the MI5 program in Ian McEwan’s novel that promotes conservative politics in Britain in the 1970s by secretly funding artists and intellectuals who lean to the right. Sweet Tooth is a good name for the operation because it means nothing. But the name of a novel should be rich with meaning, hinting at deep layers of significance and irony, like Sweet Tooth. That’s McEwan’s sugar-coated novel of spies, writers, and love.

Four loves, in fact. Serena Frome is a bookish and beautiful young Cambridge student whose boyfriend (1) introduces her to a retired spy (2) who gets her a secretarial job at MI5 with a dashing agent (3) who assigns her to dupe a promising novelist (4) into supporting their cause. Serena falls for all of these men, especially the promising novelist. He is a writer of mainstream literary fiction that offers a rather nostalgic and patriotic view of Britain, but his name is not Ian McEwan—it’s Tom Haley. Tom falls for Serena’s cover story, which is that she works for an arts foundation and the money she’s giving him is perfectly innocent. It doesn’t take a master spy to see where this is heading. Serena loves Tom, but their relationship is based on a deception, and her dalliance with him threatens to unravel the whole Sweet Tooth operation. Imagine a James Bond novel from the perspective of a lusty Moneypenny, or a Graham Greene re-write of The Best of Everything.

McEwan treats the bra-burning, pot-smoking, Soviet-bashing Cold War era with the same ambition he brought to the country estates and nightmarish World War II hospitals of his wildly successful Atonement. Serena’s MI5 office is a vibrant and perilous place, like Mad Men but with all of global capitalism hanging in the balance. For Serena the political is always personal, mostly because she can’t keep her hands off the “clever, amoral, inventive, destructive men” who are drawn to the Security Service. This makes her an ideal narrator for readers with a taste for high drama, as treason and heartbreak follow her everywhere. “Civilization threatened by a nuclear war,” Serena thinks, “and I’m brooding about a stranger who caressed my palm with his thumb. Monstrous solipsism.” Indeed. In her spare time Serena reads middlebrow fiction by the shelf-full, so she doesn’t need to be reminded that espionage is always a kind of fiction. But the dashing agent (3) reminds her anyway: “In this line of work, the line between what people imagine and what’s actually the case can get very blurred. In fact that line is a big gray space, big enough to get lost in.” Serena proceeds to lose herself completely in the Tom Haley affair.

While his broad strokes are often coarse, McEwan in the particulars can be acute. He approaches Serena’s romance with the retired spy (2), for example, with the cold precision of a surgeon, and like surgery it’s startling and raw and hard to look away from. Other bits, like Serena’s analysis of office power dynamics (which McEwan, tempting fate, adapts from primary sources) feel like a social studies paper. McEwan’s logical voice doesn’t always suit Serena, who is motivated by what the retired spy (2) calls akrasia—acting against one’s better judgment. But this may not be McEwan’s fault, exactly. There is a single, sweeping metafictional game at play in Sweet Tooth. It will either take your breath away or send you tearing back through the pages, furiously noting how McEwan has absolved himself of his novel’s flaws. (If you’ve read Atonement, you already know this game.) At the very least McEwan is having fun—writing his friend Martin Amis into the story at a young age, cracking wise about the Booker Prize, which he won, and needling the Paris Review.

But this is a spy novel, and spy novels end with explosions. Sweet Tooth keeps on detonating until the end. It’s astonishing how fully McEwan has mastered his particular set of skills, even if his confection tastes factory-made.